K-spar configuration for bonded wing construction

ABSTRACT

A method and apparatus of bonded wing construction in which skins ( 35, 39 ) having shaped protrusions ( 37, 41 ) are bonded to rib members having correspondingly shaped intrusions ( 33 ). The skins may also include differently shaped protrusions ( 53, 55 ) which are bonded to K-shaped spars ( 51 ) having correspondingly shaped intrusions ( 61, 63 ).

TECHNICAL FIELD

[0001] The present invention relates to aircraft wing construction. Inparticular, the present invention relates to a method and apparatus fora bonded wing construction.

DESCRIPTION OF THE PRIOR ART

[0002] Traditionally, aircraft wing structures were constructed byfastening C-shaped channel spars to the ends of ribs and by mechanicallyfastening I-beam-stiffened skins to angle clips disposed in channels inthe wing ribs. These systems rely purely on mechanical assembly for sparto skin and skin to rib interfaces.

SUMMARY OF THE INVENTION

[0003] There is a need for a bonded wing construction which does notrely purely upon mechanical assembly to establish the necessary spar toskin and rib to skin interfaces without compromising the stiffness ofthe wing.

[0004] Therefore, it is an object of the present invention to provide amethod and apparatus for bonded wing construction that does not relypurely upon mechanical assembly to effectuate the skin to rib interfaceand the spar to rib interface, and which does not sacrifice wingstiffness.

[0005] The above objects are achieved by providing a method andapparatus of bonded wing construction in which skins having generallyrhombus shaped protrusions are bonded to rib members havingcorrespondingly shaped intrusions. The skins may also include triangularshaped protrusions which are bonded to K-shaped spars havingcorrespondingly shaped intrusions.

[0006] The present invention has significant advantages, including: (1)only about 5% mechanical assembly; (2) less complex assembly; (3) areduction in part counts, detail fabrication, assembly fastenerinstallation, and associated assembly recurring costs; (4) a reductionin the complexity of assembly tool design and non-recurring toolprocurement costs; and (5) reduction in skin manufacturing costs andcycle time.

[0007] The above objects and advantages, as well as others, will beevident from the following detailed description of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is an assembly view of a prior-art wing structure.

[0009]FIGS. 2A and 2B are assembly views of the K-spar bonded structureconfiguration of the present invention.

[0010]FIG. 3 illustrates the bond socket concept of the presentinvention.

[0011]FIG. 4 is an enlarged view of the bond socket concept of FIG. 3for a forward spar.

[0012]FIG. 5 is an enlarged view of the bond socket concept of FIG. 3for an aft spar.

[0013]FIG. 6 is an assembly view of the K-spar bonded structureconfiguration of the present invention used in a torque box application.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0014] Referring to FIG. 1 in the drawings, a prior-art wingconstruction is illustrated. A rib 11 includes channels 13 into whichare mechanically installed angle clips 15. Angle clips 15 aremechanically coupled to I-beams 17 carried by an upper stiffened skin 19and a ;lower stiffened skin 21. A C-shaped spar 23 is coupled to rib 11and/or upper and lower skins 19 and 21. This is a typical mechanicalassembly which requires a relatively large number of parts and whichrequires a complex assembly process.

[0015] Referring now to FIGS. 2A and 2B in the drawings, the K-sparbonded structure configuration of the present invention is illustrated.A rib 31 includes a plurality of generally rhombus shaped intrusions 33.An upper stiffened skin 35 includes a plurality (only one shown) ofgenerally correspondingly rhombus shaped protrusions 37 that are alignedwith rib intrusions 33 on the upper surface of rib 31. In a similarfashion, a lower stiffened skin 39 includes a plurality (only one shown)of generally correspondingly rhombus shaped protrusions 41 that arealigned with rib intrusions 33 on the lower surface of rib 31. It shouldbe understood that the geometric shape of the protrusions can varywidely from application to application.

[0016] A K-shaped spar, or K-spar, 51 is configured to conform to theend of rib 31. As best seen in FIG. 2B, K-spar 51 is also wedge shapedin the vertical direction, having a protruding ridge 57 which mates withan intruding channel 59 in one or more ribs 31. Upper skin 35 includes atriangular protrusion 53. Likewise, lower skin 39 includes a triangularshaped protrusion 55. K-spar 51 includes an upper triangular intrusion61 and a lower triangular intrusion 63. It should be understood thatupper and lower triangular intrusions 61 and 63 may be of other shapes.

[0017] Skin 35 includes a tab portion 65, and skin 39 includes a tabportion 67. K-spar 51 includes corresponding upper and lower tabportions 69 and 71.

[0018] When assembled and bonded together using conventional techniquesand bonding materials, protrusions 37 on upper skin 35 and protrusions41 on lower skin 39 interlockingly mate with intrusions 33 in rib 31;protrusions 53 on upper skin 35 and protrusions 55 on lower skin 39interlockingly mate with upper intrusions 61 and lower intrusions 63,respectively on K-spar 51; and tab portions 65 and 67 mate with tabportions 69 and 71, respectively. Also, protruding ridges 57interlockingly mate with channels 61. This configuration provides largesurface areas for which to bond these component parts together andcreate a stiff structure. This can be done with only about 5% mechanicalassembly, as opposed to the 100% mechanical assembly associated with theprior art.

[0019] Referring now to FIG. 3 in the drawings, the assembled and bondedstructure is illustrated. The bonding pattern is shown in bold.

[0020] Referring now to FIG. 4 in the drawings, an enlarged view of aforward K-spar and the bond socket concept according to the presentinvention is illustrated. The bonding pattern is shown in bold.

[0021] Referring now to FIG. 5 in the drawings, an enlarged view of aforward K-spar and the bond socket concept according to the presentinvention is illustrated. The bonding pattern is shown in bold.

[0022] It should be understood that the method of the present inventioncan be used to configure a wide variety of structures, not just aircraftwings.

[0023] Referring now to FIG. 6 in the drawings, the present invention isillustrated in a torque box application.

[0024] The present invention has significant advantages, including: (1)only about 5% mechanical assembly; (2) less complex assembly; (3) areduction in part counts, detail fabrication, assembly fastenerinstallation, and associated assembly recurring costs; (4) a reductionin the complexity of assembly tool design and non-recurring toolprocurement costs; and (5) reduction in skin manufacturing costs andcycle time.

[0025] Although the present invention is shown in a limited number offorms, it is not limited to just these forms, but is amenable to variouschanges and modifications without departing from the spirit thereof.

1. A structure for an aircraft, comprising: a rib spar having first andsecond opposed surfaces, and at least one end surface connecting thefirst and second opposed surfaces, wherein the first and second opposedsurfaces each have at least one intrusion therein; a K-spar bonded tothe rib spar end surface, the K-spar having first and second intrusionsrespectively adjacent the first and second rib spar opposed surfaces; afirst skin member bonded to the first rib spar surface, wherein thefirst skin member has a first protrusion near an end thereof adapted tofit into the K-spar first intrusion, and at least one additionalprotrusion adapted to fit into the rib spar first surface intrusion; anda second skin member bonded to the second rib spar surface, wherein thesecond skin member has a first protrusion near an end thereof adapted tofit into the K-spar second intrusion, and at least one additionalprotrusion adapted to fit into the rib spar second surface intrusion. 2.The structure of claim 1, further comprising: at least one end intrusionin the rib spar end surface; and corresponding at least one protrusionon the K-spar, wherein the K-spar protrusion is adapted to fit into therib spar end surface intrusion.
 3. The structure of claim 2, wherein therib spar end surface intrusion has a triangular cross-section, and theK-spar protrusion has a matching triangular cross-section.
 4. Thestructure of claim 1, wherein the K-spar first and second intrusionseach have a triangular cross-section, and wherein the first and secondskin member first protrusions each have a triangular cross-section thatmatches the K-spar first and second intrusions, respectively.
 5. Thestructure of claim 1, wherein the rib spar first and second opposedsurface intrusions have a rhombus-shaped cross-section, and the firstand second skin member protrusions each have a rhombus-shapedcross-section that matches the rib spar first and second opposed surfaceintrusions.
 6. The structure of claim 1, wherein the rib spar has asecond end surface opposite the end surface, and further comprising: asecond K-spar bonded to the rib spar second end surface, the secondK-spar having first and second intrusions respectively adjacent thefirst and second rib spar opposed surfaces; wherein the first and secondskin members additionally have second protrusions near respective secondends thereof, such second intrusions adapted to fit into the secondK-spar first and second intrusions, respectively.
 7. The structure ofclaim 1, wherein the K-spar includes at least one protrusion extendingaway from the rib spar end surface, and approximately coplanar with therib spar first surface, and wherein the first skin member includes aprojecting portion at the end that is bonded to the K-spar protrusion.8. A method for assembling a structure for an aircraft, comprising thesteps of: providing a rib spar having first and second opposing surfacesand at least one end surface, the first and second opposing surfaceseach having at least one intrusion therein; bonding a K-spar to the ribspar end surface, wherein the K-spar has first and second intrusionstherein adjacent the rib spar first and second surfaces; and bondingfirst and second skin members to the first and second rib spar surfaces,respectively, wherein the first and second skin members each haveprotrusions corresponding to, and adapted to mate with, the rib sparsurface intrusions and the K-spar first and second intrusions,respectively.
 9. The method of claim 8, wherein the bonding stepscomprise bonding the spars and members together with a bonding material.